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From: Vince Weaver <vincent.weaver@maine.edu>
X-Google-Original-From: Vince Weaver <vince@maine.edu>
Date: Wed, 7 Sep 2016 23:36:06 -0400 (EDT)
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To: Alexander Shishkin <alexander.shishkin@linux.intel.com>
cc: Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        eranian@google.com, Arnaldo Carvalho de Melo <acme@infradead.org>,
        vincent.weaver@maine.edu
Subject: Re: [PATCH v2 0/5] perf, bts: Fallout from the fuzzer for
 perf/urgent
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References: <20160906132353.19887-1-alexander.shishkin@linux.intel.com> <20160906171915.GA8963@gmail.com> <87mvjjka7u.fsf@ashishki-desk.ger.corp.intel.com> <alpine.DEB.2.11.1609071135030.1004@pianoman.cluster.toy>
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On Wed, 7 Sep 2016, Alexander Shishkin wrote:

> Vince Weaver <vince@deater.net> writes:
> 
> > On Wed, 7 Sep 2016, Alexander Shishkin wrote:
> >
> >> Sure. And yes, I did catch a warning, which calls for one more patch
> >> (below). Also one unrelated thing in PEBS that Peter fixed.
> >
> > Does that fix this which I just got on my skylake machine (4.8-rc5 with 
> > your other 5 patches applied)
> >
> > [ 5351.822559] WARNING: CPU: 3 PID: 19191 at arch/x86/events/intel/bts.c:344 event_function+0xa1/0x160
> 
> Yes, it fixes a problem that triggered this warning. Can't tell from the
> absence of backtrace what's going on here, though.

On the skylake machine with the original 5 patches I got this after 
continuing to fuzz.  Sorry about the lack of frame pointer, next
compile will have it enabled.

If it matters, prior to this I hit the unrelated
[25510.278199] WARNING: CPU: 1 PID: 25405 at kernel/events/core.c:3554 perf_event_read+0x18f/0x1a0


[28682.174684] WARNING: CPU: 7 PID: 31992 at kernel/events/core.c:4961 perf_mmap_close+0x2e1/0x2f0
[28682.280579] CPU: 7 PID: 31992 Comm: perf_fuzzer Tainted: G        W       4.8.0-rc5+ #3
[28682.288739] Hardware name: LENOVO 10FY0017US/SKYBAY, BIOS FWKT53A   06/06/2016
[28682.296096]  0000000000000286 000000008e07b373 ffffffff8cf1f9f5 0000000000000000
[28682.303738]  0000000000000000 ffffffff8cc7b624 ffff9c676e780e00 ffff9c676e029280
[28682.311362]  ffff9c6772ab3398 ffff9c676e029000 ffff9c676e780bb0 ffff9c676f7c0280
[28682.319036] Call Trace:
[28682.321529]  [<ffffffff8cf1f9f5>] ? dump_stack+0x5c/0x77
[28682.326939]  [<ffffffff8cc7b624>] ? __warn+0xc4/0xe0
[28682.332018]  [<ffffffff8cd6dc01>] ? perf_mmap_close+0x2e1/0x2f0
[28682.338083]  [<ffffffff8cd664b0>] ? perf_iterate_ctx+0x150/0x150
[28682.344218]  [<ffffffff8cdb5e7d>] ? remove_vma+0x2d/0x70
[28682.349662]  [<ffffffff8cdb84d6>] ? do_munmap+0x246/0x400
[28682.355197]  [<ffffffff8cdb8c1b>] ? SyS_munmap+0x4b/0x70
[28682.360612]  [<ffffffff8cc03b6f>] ? do_syscall_64+0x5f/0x160
[28682.366404]  [<ffffffff8d1e7b65>] ? entry_SYSCALL64_slow_path+0x25/0x25
[28682.373149] ---[ end trace bc7b0b7d0c024d62 ]---
[28682.377975] ------------[ cut here ]------------
[28682.382681] WARNING: CPU: 4 PID: 0 at kernel/events/ring_buffer.c:543 __rb_free_aux+0x110/0x120
[28682.489412] CPU: 4 PID: 0 Comm: swapper/4 Tainted: G        W       4.8.0-rc5+ #3
[28682.498106] Hardware name: LENOVO 10FY0017US/SKYBAY, BIOS FWKT53A   06/06/2016
[28682.506518]  0000000000000086 6d2f07ae6326ed5e ffffffff8cf1f9f5 0000000000000000
[28682.515223]  0000000000000000 ffffffff8cc7b624 ffff9c676e780e00 ffff9c677dd0b740
[28682.523996]  0000000000000000 ffff9c676e029000 ffff9c676e780e00 00001a16168dab54
[28682.532867] Call Trace:
[28682.536458]  <IRQ>  [<ffffffff8cf1f9f5>] ? dump_stack+0x5c/0x77
[28682.543615]  [<ffffffff8cc7b624>] ? __warn+0xc4/0xe0
[28682.549741]  [<ffffffff8cd700e0>] ? __rb_free_aux+0x110/0x120
[28682.556829]  [<ffffffff8cd70f3a>] ? perf_aux_output_end+0xba/0x100
[28682.564312]  [<ffffffff8cc0c9e1>] ? bts_event_stop+0xc1/0x130
[28682.571238]  [<ffffffff8cd63a00>] ? perf_cgroup_attach+0x70/0x70
[28682.578402]  [<ffffffff8cd621f0>] ? __perf_event_stop+0x40/0x60
[28682.585484]  [<ffffffff8cd63a3a>] ? remote_function+0x3a/0x40
[28682.592644]  [<ffffffff8ccfad46>] ? flush_smp_call_function_queue+0x76/0x160
[28682.600867]  [<ffffffff8cc4e6e9>] ? smp_trace_call_function_single_interrupt+0x29/0xc0
[28682.609914]  [<ffffffff8d1e9ce2>] ? trace_call_function_single_interrupt+0x82/0x90
[28682.618608]  <EOI>  [<ffffffff8d0a9d13>] ? cpuidle_enter_state+0x113/0x260
[28682.626570]  [<ffffffff8ccbd7dc>] ? cpu_startup_entry+0x2cc/0x370
[28682.633675]  [<ffffffff8cc4f07d>] ? start_secondary+0x14d/0x190
[28682.640749] ---[ end trace bc7b0b7d0c024d63 ]---